In general, a lead-acid storage battery can be broadly classified into a paste type one and a clad type one. The paste type lead-acid storage battery comprises pasted positive plates and pasted negative plates while the clad type lead-acid storage battery comprises positive plates having active material clad with successive integral tubes of porous insulating material and pasted negative plates. They are placed in a case so that they are alternately arranged, with an insulating separator provided between the adjacent positive and negative plates, and so that they are immersed in an electrolyte of dilute sulfuric acid. Generally, the paste type lead-acid storage battery is suitably used in the event that a good starting property is required while the charge and discharge are repeated at higher frequency, but it has the disadvantage of short life. On the other hand, the clad type lead-acid storage battery is suitably used in the event that the charge and discharge are repeated at lower frequency, but has the disadvantages that it has lower energy and output densities and that it cannot be adapted to mass production.
A lead-acid storage battery which is adapted to be used for an electric car requires improvement in the energy and output densities and its mass production, as well as its long life. There has been provided no lead-acid storage battery that can meet all the requirements.